The present invention relates to vehicle cabin air filters, to vehicles including such filters, and to methods of manufacturing such filters.
More particularly, the invention relates to a vehicle cabin air filter comprising a filter material adapted to retain particles in suspension in the air.
An object of the present invention is specifically to improve known filters of this type, so as to enable them to diffuse volatile substances into the vehicle cabin.
To this end, the invention provides an air filter of the kind in question, wherein the filter material carries microcapsules which contain at least one volatile substance and which are adapted to diffuse said volatile substance progressively into the air passing through the filter, wherein the microcapsules are of a diameter lying in the range 0.5 xcexcm to 20 xcexcm; and wherein the microcapsules are of a size that is smaller than the maximum size of the pores of the filter material.
By means of these dispositions, it is possible to diffuse substances such as fragrances, antibacterial compounds, substances that neutralize odors or pollutants, mixtures of such substances, etc. into the cabin of the vehicle.
Presenting the volatile substance in the form of microcapsules makes it possible:
to conserve the volatile substance under optimum conditions prior to using the filter;
to use a wide range of volatile substances almost independently of any chemical compatibility with the filter medium, given that the volatile substance is isolated within the walls of the microcapsules prior to being diffused in the air; and
to use methods that are relatively easy to implement and of low cost when depositing microcapsules on the filter material, thus leading to a filter of moderate price.
These dispositions also make it possible to avoid significantly increasing the head loss through the air filter.
In preferred embodiments of the air filter of the invention, use can optionally also be made of one or more of the following dispositions:
the microcapsules are distributed over at least a portion of the thickness of the filter material;
the volatile substance contained in the microcapsules contains at least one substance selected from:
fragrances;
antibacterial agents; and
substances suitable for neutralizing gases contained in air;
the volatile substance contained in the microcapsules is selected from substances that are liposoluble and substances that are hydrosoluble;
each microcapsule has a thin outer wall made of a material selected from porous aminoplast polymers, polyamide polymers, polyurethane polymers, and cellulose polymers;
the microcapsules adhere to the filter material by chemical compatibility;
the microcapsules adhere to the filter material by means of a chemical binder; and
the binder is selected from polyurethane binders, polyamide binders, silicone binders, acrylic binders, and epoxy binders.
The invention also provides a motor vehicle having at least one filter as defined above to filter the air delivered to the vehicle cabin.
Finally, the invention also provides a method of manufacturing a filter as defined above, in which method the microcapsules are deposited on the filter medium by means of a method selected from:
padding;
coating;
spraying;
bath depletion;
silk-screen printing;
passing the filter material over at least one cylinder turning in a liquid containing microcapsules; and
offset printing.